IT’S a common mistake, but still worth noting: Contrary to what many people seem to think, The Sixth Sense was not M. Night Shyamalan’s first movie.

It was, in fact, his third. But virtually no one had seen his first film, Praying with Anger (still not available on DVD), or his second film, Wide Awake (with Rosie O’Donnell as a nun who really likes baseball).

So when The Sixth Sense came out in the summer of 1999 and wowed audiences with its deeply felt drama and its shocking twist ending — becoming such a big word-of-mouth hit that, for the next couple years, it was one of the top 10 films of all time at the North American box office — it was easy for many people to treat the film as though it marked the debut of a brilliant and brand-new talent.

SIGNS IS a daring bait-and-switch, in which director M. Night Shyamalan seems to promise his audience a movie about aliens and gives us a movie about God, instead. The film, which stars Mel Gibson as an Episcopal priest who has lost his faith following the tragic death of his wife, is about the need to believe that there is someone out there watching over us, and not just some empty meaningless void, and the film cannily plays with — and rejects — the idea that aliens can fulfill this need.